1. Field of the Invention
The present invention relates generally to computer systems and more particularly to a computer system that includes a reusable isolated undo/redo service that provides application programs with an undo/redo function.
2. Description of the Prior Art
The undo and redo functions are available in many of the products available on the market today. The undo function should be able to reverse actions that the user has decided should not have been performed. The redo function simply reverses the action that was undone most recently. To accomplish this, both functions must save information that would otherwise be lost so that it may be recovered upon user request. For example, to undo a delete, the data that was deleted must be saved. Similarly, to redo a paste, the data that was "unpasted" must be saved so that it may be pasted back. Some applications allow users to undo more than just the last action. This capability is usually called multi-level undo. Given the myriad of applications and the variety of data they support, it has proven extremely difficult to implement the undo function in such a way that it provides a clean interface into a wide variety of applications. As a result, this function is often tightly integrated into each individual application and is not reusable from one application to another without major modification.